Labour MP Stuart Nash has said sorry to Newshub political reporter Jenna Lynch after telling her she looked as though she'd had a "rough night".

In a blog, Ms Lynch called out Mr Nash for commenting on her face, which was not covered by any makeup, as he arrived to speak to her at Newshub's Wellington office.

"Labour MP Stuart Nash walked in trying to sell some bloody story about cops. He looked shocked, almost offended at my face," she wrote.

"'Gosh, did you have a rough night?' No I didn't. Unless you call being curled on the couch watching a movie with my partner a "rough night"."

Ms Lynch said in her blog Mr Nash should be ashamed over his comments.

"I feel sorry for the women you work with on a day-to-day basis if you hold them to the same standard."

However, he's now apologised for his remark.

"Look, I don't go out of my way to offend anyone at all - I'm very apologetic," he said.

"I'm sorry that Jenna took offence and I apologise unreservedly - I completely regret saying what I did."

Ms Lynch responded to Mr Nash's apology by saying he's "a good guy" - but said his off-the-cuff quip was part of "a wider issue".

"We do have a good rapport and he probably just thought he was making a bit of a joke - that's fine," she said.

"But this is an issue about beauty standards and what is expected of us as women. I was just sitting at my desk, reading through an OIA [and] trying to figure out what was happening in the big wide world of Parliament so that I can bring you the news.